Electric incandescent body



May 19, 1931. w. NODDACK ET AL 1,806,410

ELECTRIC INCANDESCENT EDDY Filed March 13. 1 29 Patented May 19, 1931UNITED STATES PATENT OFFICE WALTER NODDACK .AND IDA NODDACK, OFBERLIN-GRUNEWALD, GERMANY, AS!- SIGNORS TO SIEMENS & HALSKE,AKTIENGFSELLSCHAFT. F SIEMENSSTADI, NEAR BERLIN, GERMANY, A CORPORATIONOF GERMANY ELEUIB-IC INCANDESCENT BODY Application filed March 13, 1929,Serial .No. 346,766, and in Germany April 12, 1928.

Our invention relates to improvements in electric incandescent bodies,more particularly such as'may be used in electric incandescent lamps,vacuum tubes, and the like, i. e. bodies or members, more specificallyfilaments, heated to high temperatures in a vacuum or an atmosphere ofan inert gas (such as nitrogen or precious gases).

Our invention consists of an incandescent body, which consists oftungsten and ekamanganese 75.

This incandescent body or member has a core of tungsten and an envelopeor coating enclosing said core consisting of eka-manganese 7 5 or of analloy of eka-manganese 75 and tungsten.

Eka-manganese 75, or rhenium, is a recently discovered metal which hasbeen introduced and described in the following publications 1. Noddackund Tacke, Die Ekamangane in the paper Die Naturwissenschaften, 13thyear, No. 26.

2. Report of Sessions of the Prussian Academy of Sciences, 1925, No.XIX.

Noddack, Darstellung und Einige Chemische Eigenschaften des Rheniums inthe Zeitschrift fiir Physikalische Chemie, volume 125, No. 3/4.

4. Noddack, Die Sauerstofiverbindungen des Rheniums in Zeitschrift fiirAnorganische Chemie, volume 181, No. 1/2.

In the drawing aflixed hereto and forming part of our specification ourimproved incandescent body or filament is enclosed in the bulb of anordinary incandescent lamp, the filament as well as the bulb being shownin sectional elevation.

Referring to the single figure of the drawing a is the core consistingof tungsten and b the envelope ,or coating consisting of ekamanganese 75or of a tungsten eka-manganese allo It? has been ascertained that suchan incandescent body is able to sustain a considerelectric current. By athin coating or film of elm-manganese 75 this atomization isconeka-manganese the advantage of cheapness.

Various modifications and changes may be made Without departing from thespirit and the scope of the invention, and we desire, therefore, thatonly such limitations shall be placed thereon as are imposed by theprior art.

We claim as our invention:

1. An electric incandescent body applicable to electric incandescentlamps, vacuum tubes and similar purposes, consisting of a core oftungsten with a coating containing eka-manganese 7 5.

2. An electric incandescent body applicable to electric incandescentlamps, vacuum tubes and similar purposes, consisting of a core oftungsten with a coating of eka-manganese 75, which is alloyed withtungsten.

In testimony whereof we aflix our signatures.

WALTER NODDACK. IDA NODDACK.

little above 3600 F. w on traversed by the

